1. Technical Field
The present invention relates to rotating electric machines that are used in, for example, motor vehicles as electric motors and electric generators.
2. Description of Related Art
There are known rotating electric machines that are used in motor vehicles as electric motors and electric generators. These rotating electric machines generally include a rotor functioning as a field and a stator disposed in radial opposition to the rotor and functioning as an armature. Moreover, the stator includes a stator core and a stator coil. The stator core has a plurality of slots arranged in a circumferential direction thereof. The stator coil is wound on the stator core so as to be partially received in the slots of the stator core with a pair of annular coil ends respectively protruding from an opposite axial end faces of the stator core.
In the above rotating electric machines, the stator coil generates heat upon being supplied with electric current. Therefore, to prevent burnout of the rotating electric machines, it is necessary to cool them. To this end, there are disclosed, for example in Japanese Patent Application Publications No. JP2012210027A and No. JP2007020334A, cooling structures for cooling the coil ends of the stator coil with cooling liquid supplied by a cooling liquid supplier to the coil ends.
However, with the cooling structures disclosed in the above patent documents, most of the cooling liquid, which is supplied to the coil ends of the stator coil from the directly or obliquely upper side, falls down through void spaces formed between electric conductor wires constituting the coil ends. That is, most of the cooling liquid wastefully falls down without sufficiently fulfilling the cooling function.
On the other hand, to sufficiently fulfill the cooling function, it is preferable for the cooling liquid to flow downward along the outer peripheries of the annular coil ends while cooling them.
In addition, the rotating electric machines are generally driven by a drive circuit. However, electrical components of the drive circuit also generate heat during operation. Therefore, it is desirable to effectively cool the electrical components, thereby making it possible to minimize the size and improve the performance of the drive circuit.